Multiple flash bulb holder



4 Sheets-Sheet l IN V EN TOR. RICHARD WICK @EL 21, R W|CK MULTIPLE FLASHBULB HOLDER Filed July 2l, 1966 2. .wm m. F

UCL 21, 1969 R, W'CK MULTIPLE FLASH BULB HOLDER 4 Sheets-Sheet 2 FiledJuly 2l. 1966 IN V EN TOR.

RICHARD WICK 0d. 21, 1969 R, WICK' 3,473,880

MULTIPLE FLASH BULB HOLDER Filed July 2l, 1966 4 Sheets-Sheet 5 F ig.575a IN VEN TOR. RICHARD WICK Oct. 21, 1969 R, WICK MULTIPLE FLASH BULBHoLDER 4 Sheets-Sheet 4 Filed July 2l, 1966 INVENTOR. RICHARD WICK Cl.431-95 12 Claims ABSTRACT 0F THE DISCLOSURE A multiple flash bulb holderwith a series of discrete flash bulbs each having two main contactsconnected to each other by a filament which is destroyed on firing ofthe respective flash bulb. The electric circuit of the holder comprisesnormally open switches installed in the flash bulbs and arranged toclose in response to firing of the respective flash bulbs to therebyprepare the next-following bulb for firing. Each switch is connected inseries between one of two terminals in the electric circuit and one mainContact of the respective flash bulb. The other main contact of eachflash bulb is connected to the other terminal.

The present invention relates to flash units in general, and moreparticularly to an improved multiple flash bulh holder which may beutilized in a photollash unit. Still more particularly, the inventionrelates to a multiple flash bulb holder whose dash bulbs can lbe red in`a predetermined sequence.

It is already known to provide a holder with two or more flash bulbs andto utilize a multi-stage switch for firing the flash bulbs in a desiredsequence. It is also known to replace the multi-stage switch with aseries of resistors having different resistances. Such holders must beprovided with complicated and expensive electric circuits.

Accordingly, it is an important object of the present invention toprovide a novel and improved multiple flash bulb holder wherein theflash bulbs are automatically fired in a given sequence and wherein suchsequential firing can be insured by resorting to a very simple andinexpensive electric circuit.

Another object of the invention is to provide a multiple flash bulbholder wherein only one of several flash bulbs can be connected in theflash circuit at a time and wherein sequential firing of flash bulbsrequires no changes Y tical number of flash bulbs and wherein such flashbulbs can be arrayed in a number of different ways.

An additional object of the invention is to provide a novel system ofvery simple switches which can be utilized in the flash bulbs of myimproved holder and which can be actuated in automatic response tochanges in temperature which develop when the respective flash bulb isfired to thereby prepare the next flash bulb for firing.

A concomitant object of the invention is to provide the flash bulbs ofmy improved holder with novel circuit completing means which reactautomatically to firing of such flash bulbs and which, if desired, maybe constructed and assembled in such a way that their operation isinsured in any desired position of inclination of the holder.

A further object of the invention is to provide a multiple flash bulbholder wherein the flash bulbs can be fired hired States arent 0Patented Oct. 21, 1969 ICC in a predetermined sequence and whichfunctions properly irrespective of the magnitude of firing voltage andirrespective of the internal resistance of individual flash bulbs.

Briefly stated, one feature of my invention resides in the provision ofa multiple flash bulb holder whose housing is preferably provided with astandard foot so that it can be introduced into a standard socketforming part of a flash unit which is built into or is usable inconnection with a photographic camera. The holder comprises a pluralityof flash bulbs each of which is preferably accommodated in a separaterecess of the housing, these flash bulbs including a first and at leastone second flash bulb, and the holder further comprises an electriccircuit at least a portion of which may be printed directly onto thehousing. This circuit has a pair of terminals which are connectable witha source of electrical energy and normally open switch means preferablyprovided in the envelope of the first flash bulb and arranged to closepermanently in response to firing of the first flash bulb to thusprepare the second flash bulb for firing.

In accordance with a more `specific feature of my invention, each flashbulb comprises a first and a second main contact and a filament whichconnects the two main contacts and is destroyed in response to firing ofthe respective flash bulb. The first main contacts of all flash bulbsare connected to one terminal of the aforementioned circuit and thesecond main contact of the first flash bulb is connected with the otherterminal so that, when the circuit is completed, the filament of thefirst flash bulb will be destroyed. The first flash lbulb furthercornprises an auxiliary contact which is normally insulated from thesecond main contact of the first flash bulb and is connected with thesecond main contact of the second flash bulb. The first flash bulb alsocomprises circuit completing means for connecting its second maincontact with the auxiliary contact in response to firing of the firstflash bulb whereby the second main contact of the second flash bulb isautomatically connected with the second terminal.

The circuit completing means may include a body of current-conductingmaterial which melts or expands strongly at firing temperature, or suchmeans may include a resilient element of current-conducting materialwhich tends to engage the auxiliary contact and is free to do so whenthe filament of the first flash bulb is destroyed.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved multiple flash bulb holder itself, however, both as to itsconstruction and its mode of operation, together with additionalfeatures and advantages thereof, will be best understood upon perusal ofthe following detailed description of certain specific embodiments withreference to the accompanying drawings, in which:

FIG. 1 is a somewhat schematic front elevational view of a multipleflash bulb holder with four flash bul-bs which is constructed inaccordance with a first embodiment of my invention;

FIG. 2 is an enlarged transverse vertical section as seen in thedirection of arrows from the line II-II of FIG. 1;

FIG. 3 is a front elevational view of a modified multiple flash bulbholder with six flash bulbs;

FIG. 4 is a perspective view of -a still camera having a builtir1 flashunit which comprises a standard socket receiving the foot of themultiple flash bulb holder shown in FIG. 3;

FIG. 5 illustrates a portion of a flash circuit including the circuit ofthe holder shown in FIGS. 1 and 2;

FIG. 6 is a fragmentary axial section through a flash bulb which isprovided with a first type of circuit completing means including a bodyof fusible currentconducting material;

FIG. 7 is a similar fragmentary axial section through a second flashbulb whose circuit completing means comprises a resilient element; and

FIG. 8 is a fragmentary axial section through a third flash bulb Whosecircuit completing means comprises a body of current-conducting materialwhich expands in response to heating.

Referring first to FIGS. l and 2, there is shown a multiple flash bulbholder comprising a relatively flat housing or support 1 which mayconsist of synthetic plastic material. The front face of the support 1is provided with a row of four recesses 2, 3, 4 and 5 which respectivelyaccommodate flash bulbs 6, 7, 8 and 9. The surfaces bounding therecesses 2-5 may be coated with strongly light-reflecting orlight-dispersing metallic material which is sprayed onto the housing 1or is applied in the form of a foil or the like. Each such layer or foilthen forms a reflector which can reflect artificial light against thesubject when the circuit of the respective flash bulb is completed. Ifdesired, the surfaces bounding the recesses 2-5 may be formed withdepressions and/or raised portions to further enhance their lightreflecting and dispersing action.

Each of the flash bulbs 6-9 comprises an envelope `which accommodatestwo main contacts 11, 12 connected to each other by a filament 10, and athird or auxiliary contact 13.

The housing 1 is also provided with a foot or plug 1a carrying twoterminals 14, which are glued or other- Wise affixed to its front andrear surfaces, respectively. The dimensions of the foot 1a preferablyequal the dimensions of a standard foot on a conventional multiple flashbulb holder so that this foot can be readily inserted into a standardsocket of a photographic camera.

The base 1b of the housing 1, which extends between the upper portion 1c(provided with the aforementioned recesses 2-5) and the foot 1a, carriesthe conductors or leads of an electric circuit which is preferably aprinted circuit and is provided in part at the front side and in part atthe rear side of the base 1b. The leads of this printed circuit areconnected with the contacts 11-13 of the flash bulbs 6-9 and with theterminals 14, 15 in a manner as illustrated in FIG. 1. A first lead 1bconnects the front terminal 14 with the main contacts 11 of the fourflash bulbs 6-9. A second lead 17 connects the rear terminal 15 with themain Contact 12 of the first (leftmost) flash bulb 6. Additional leads18-20 respectively connect the auxiliary contacts 13 of flash bulbs 6,7, 8 with the main contacts 12 of the flash bulbs 7, 8, 9. The auxiliarycontact 13 of the last (rightmost) flash bulb 9 is not connected in thecircuit at all and is provided solely because the flash bulbs 6-9 arepreferably identical with each other to reduce the manufacturing cost.This last flash bulb 9 can be replaced by a conventional flash bulbhaving a pair of contacts corresponding to the main contacts 11, 12 ofany one of the flash bulbs 6-9. The leads 16 and 18-20 are provided atthe front side of the base 1b and are shown in FIG. l by solid lines.rIhe lead 17 is provided at the rear side of the base 1a and is shown inFIG. 1 by broken lines.

The function of the auxiliary contacts 13 is to automatically connect anext-following flash bulb 7, 8, 9 in circuit with the terminals 14, 15in response to firing of the preceding flash bulbs 6, 7, 8 respectively.In other words, and when the first flash bulb 6 is fired, its maincontact 12 is conductively connected with the auxiliary contact 13 andhence with the lead 18 and main contact 12 of the next-following flashbulb 7. The rear terminal 15 is then connected with the main contact 12of the flash bulb 7 through the lead 17, contacts 12, 13 of the flashbulb 6, and lead 18. The front terminal 14 is con- 4 nected with themain contact 11 of the flash bulb l through the lead 16.

When the flash bulb 7 is fired, its contacts 12, 13 automaticallyconnect the terminal 14 with the contact l2 of the flash bulb 8 throughthe contacts 12, 13 of the spent flash bulb 6. In response to ignitionof the bulb its contacts 12, 13 connect the main contact 12 of the lastflash bulb 9 with the rear terminal 15 through the contacts 12, 13 ofthe spent flash bulbs 6 and 7. In other words, each preceding flash bulb6, 7, 8 has a built-in switch 12, 13 which closes in automatic responseto firing of the respective flash bulb to connect one main contact 12 ofthe next-following flash bulb 7, 3, 9 with the rear terminal 15. Theswitches 12, 13 of all spent flash bulbs are connected in series by theleads 1S, 19, 20. The other main contact 11 of each flash bulb isdirectly connected with the front terminal 14 by the lead 16. The mannerin which the aforementioned switches 12, 13 close in response to firingof a flash bulb 6, 7 or S will be describen in connection with FIGS. 6,7 and 8. The filaments 10 are destroyed in response to firing of therespective flash bulb and terminate the current-conducting connectionbetween the corresponding main contacts 11, 12.

If the multiple flash bulb holder of FIG. 1 is attached to a stillcamera (for example, to a camera of the type shown in FIG. 4), its foot1a enters the socket of the camera and the terminals 14, 15 engagesuitable complementary contacts in the flash circuit of the camera. Suchflash circuit comprises a customary synchronizing switch and one or moresources of electrical energy ano can be completed in response toactuation of a release trigger for the shutter. The aforementionedsocket may be built into or may be detachably mounted on the camera. Inresponse to a first actuation of the release trigger Sila (see FIG. 4),the flash circuit is completed and the first flash bulb 6 is fired toilluminate the subject. Such firing results in destruction of thefilament 10 and in closing of the switch 12, 13 which connects the maincontact 12 of the second flash bulb 7 with the rear terminal 15 throughthe intermediary of the lead 18. During the next actuation of thetrigger 30a, the flash circuit is completed again and fires the secondflash bulb 7 which illuminates the subject with attendant destruction ofits filament 10 and closing of its switch 12, 13. The switch isconnected tn series with the switch 12, 13 of the spent flash bulb e andthe two switches connect the main contact 12 of the next-following freshflash bulb 8 with the rear terminal 15. The main contact 12 of the lastflash bulb *t is connected with the terminal 15 in response to closingof switches 12, 13 in all of the preceding flash bulbs b. 7 and 8.

Referring again to FIG. 2, the front sides of the four recesses 2-5 inthe upper portion 1c of the housing 1 are closed by a transparentcovering or panel 21 of synthetic plastic sheet material which is gluedor otherwise affixed to the housing. This panel 21 prevents escape offragments of envelopes if a flash bulb happens to break. Also, the panel21 preferably overlies the leads 16 and 18-20 at the front side of thebase 1b to protect such leads from damage. The entire multiple flashbulb holder forms a self-contained unit which can be mass-produced andcan be readily manipulated by unskilled amateurs. The covering 21protects the flash bulbs so that the holder of FIGS. 1 and 2 can bemanipulated by hand and stored in unpadded boxes Without any danger ofdamage or breakage.

FIG. 3 illustrates a modified multiple flash bulb holder which isprovided with six recesses 22a-27a disposed in two groups and eachaccommodating one of six flash bulbs 22-27. The housing 28 of thisholder comprises a standard foot 28a with terminals 14', 15. The printedcircuit includes front leads which are shown by solid lines and rearleads shown by broken lines. The manner in which the switches 12', 13 ofspent flash bulbs can connect the main Contact 12' of the next-following(unexpended) ash bulb with the front terminal 14' is selfexplanatory. ltis clear that the multiple iiash bulb holder of my invention maycomprise only two or three ash bulbs as well as live, seven or even moreflash bulbs, and that such dash bulbs may be distributed in any desiredway, i.e., in one or more horizontal or vertical rows, in the form of afull circle or semicircle, in the form of a cross or star, or in anyother array which does not take up too much space.

In this embodiment of my invention, the lead 16 which is connected withall of the main contacts 11 is provided at the rear side of the housing28 and is connected to the terminal Referring now to FIG. 4, there isshown a still camera whose casing 3l) has a top wall 30h provided with astandard socket 29 for the foot 28a of the housing 28. The socket 29 ispartially surrounded by a reliector 31 which is preferably depressibleso that it can be concealed in the casing 30. This reflector 31 can becoupled with a suitable ejector (not shown) which expels the foot 28afrom the socket 29 in automatic response to depression of the reflector31. It will be seen that the foot 28a is long enough to allow formovement of the reflector 31 to its fully exposed position so that theaforementioned ejector is idle. Such relatively long foot allows forattachment of the improved multiple flash bulb holder to cameras whosereliectors 31 are dimensioned for use in connection with much smallerholders, for example, those known as Flashcubes, or in connection withindividually insertable liash bulbs. The number of ilash bulbs in thehousing 28 can be selected independently of the size of the reiiector 31because the latter does not reach that (upper) part of this housingwhich accommodates the ash bulbs.

FlG. 5 illustrates the ash circuit of a camera which can utilize theimproved multiple flash bulb holder, for example, the holder which wasdescribed in connection with FlGS. l and 2. This lash circuit includes acustomary charging capacitor C1 which can be installed in the cameraproper or in a detachable flash unit. The capacitor C1 can be chargedthrough a resistor R which is connected in series with a source ofelectrical energy here shown as a battery 32. The release trigger of thecamera can close a normally open switch S to connect the battery 32 incircuit with the first iiash bulb 6. The terminals in the socket of thecamera are shown at 14a, 15a and are respectively engaged by theterminals 14, 15 on the foot of the housing which accommodates the liashbulb 6.

The capacitor C1 discharges in response to closing of the switch S toiire the ash bulb 6 and to destroy the filament 10. In response to suchdestruction of the lament 10, the switch 12, 13 of the spent ash bulb 6closes and connects the terminal 15 with the main contact 12 of thesecond ash bulb 7 through the lead 18. The capacitor C1 is recharged onopening of the switch S and, when the switch S is closed again, reneweddischarge of the capacitor C1 results in :tiring of the ash bulb 7 sothat the lament 10 of this iiash bulb is destroyed and the switch 12, 13of the liash bulb 7 connects the terminal 15 with the main contact 12 ofthe third ash bulb 8 (not shown in FIG. 5) in the same way as describedin connection with FIG. l, i.e., through the leads 17-19 and theswitches 12, 13 of the spent ilash bulbs 6 and 7.

The additional or supplementary capacitors C2, C3 shown in FIG. 5prevent premature iiring of the ash bulbs 7, 8 by the remaining chargeof the capacitor C1. The capacitors C2, C3 are connected in parallelwith the flash bulbs 7, 8, and a similar capacitor (not shown) isconnected in parallel with the fourth and last liash bulb 9. Thesesupplementary capacitors can intercept the major part of surplus currentimpulse developing on discharge ot' the capacitor C1 and thus preventsuch iiow of current which would cause iiring of the associated ash bulb7, 8 or 9 simultaneously with tiring of the preceding lash bulb 6, 7 or8.

Care should be taken to insure that the duration of the tiring impulseshould not exceed the time necessary for closing of the switch in theiiash bulb which is being red, i.e., that the switch S opens before thecapacitor C1 discharges again to re the next-following liash bulb. Suchopening of the switch S takes place automatically in presently knownflash units which utilize one or more charging capacitors.

FIG. 6 shows one embodiment of a ash bulb whose switch (including a maincontact 38 and an auxiliary contact 40) closes in automatic response totiring and resultant destruction of the iilament 36. The iiash bulbcomprises an envelope 35 of vitreous material and a second main contact37 which is connected with the main contact 38 by the iilament 36. Theinterior of the envelope 35 further accommodates a smal] receptacle 39which preferably consists of vitreous or ceramic material and does notconduct electric current. As clearly shown in FIG. 6, the cavity orchamber 39a of the receptacle 39 accommodates the bulbous head 41 of theauxiliary contact 40 and a portion of the adjoining main contact 38. Thehead 41 consists of a material which melts at temperatures developing inthe chamber 39a in response t0 tiring of the ash bulb. For example, thehead 41 may consist of a body of tin solder or silver solder. In orderto insure that melting of the head 41 will invariably result inestablishment of a current-conducting connection between the contacts 38and 40, the head may be surrounded by a layer of ux. As soon as thetemperature in the cavity 39a reaches the melting temperature of thematerial of which the head 41 consists, the latter begins to melt andforms a pool 39]: in the bottom zone of the cavity and establishes a-connection between the contacts 38 and 40. The receptacle 39 preventsshortcircuiting of the flash bulb prior to firing by holding thecontacts 37, 38 and 4G in the regions which are closely adjacent totheir upper ends. Short-circuiting of the ash bulb by remnants of themetallic filler (not shown) in the envelope 35, which ller is destroyedon tiring of the ash bulb, can be prevented by providing the contact 37with a coat of insulating material. Such insulating coat also preventsaccidental shorting by the wires of the iiller prior to actual tiringofthe flash bulb.

lf desired, the receptacle 39 can be formed as an integral part of theenvelope 35, for example, as an integral part of the base 35a. However,the provision of a separate receptacle 39 which holds the free endportions of the contacts 37, 38, 40 apart is normally preferred becausethe receptacle then prevents accidental shorting.

FIG. 7 illustrates a modied iiash bulb having an envelope 42 of vitreousmaterial, two main contacts 43, 45 connected to each other by a iilament44, and an auxiliary contact 47 having a pointed head 48. The upperportion of the main Contact 45 is constituted by a leaf spring 46 whichstores energy when the lament 44 is intact. When the filament 44 isdestroyed in response to firing of the flash bulb, the spring 46 movesto its unstressed position and engages the head 48 to close the switchwhich includes the contacts 45 and 47. The solution shown in FIG. 7 isoften preferred over that which was described in connection with FIG. 6because the spring 46 can close the switch 45, 47 regardless of theposition of inclination in which the envelope 42 is held at the time theflash bulb is tired. The spring 46 may be welded, riveted or otherwiseconductively connected with the Iemainder of the main conductor 45. Thelength of the lament 44 is selected in such a way that the spring 46remains deformed as long as the iilament remains intact, i.e., the maincontact 43 must be rigid or its flexibility must be less than that ofthe spring 46 so that the spring invariably remains spaced from the head48 as long as the circuit of the contacts 43, 45 is not completed. Thenormal position of the spring 46 is preferably selected in such a waythat this spring actually bears against the 7 head 48 when the filament44 is destroyed so that the spring does not move away from the head 48even if the multiple flash bulb holder embodying the ash bulb of FIG. 7is shaken or otherwise agitated subsequent to firing of the flash bulb.

Referring finally to FIG. 8, there is shown a third flash bulb whoseenvelope 49 accommodates two main contacts 55, 56 and an auxiliarycontact 54. The lower portion of the envelope 49 defines a preferablycylindrical cavity or chamber 50 which accommodates the pointed tip 54aof the auxiliary contact 54 and an intermediate portion of the maincontact '55. The upper end of the chamber 50 is sealed from theremainder of the internal space of the envelope 49 by a fixed stopper orcork 51. This stopper 51 is adjacent to the upper side of a mercury drop53 whose underside is adjacent to a vertically movable separator hereshown as a diaphragm 52 preferably consisting of readily penetrable softplastic material. The diaphragm 52 rests on the tip 54a of the auxiliarycontact 54. The median portion of the main contact 55' eX- tends throughthe chamber 50 and passes through the diaphragm 52, drop 53 and stopper51. The lupper'end portion of the main contact 55 is connected with themain contact 56 by a filament 57. The mercury drop 53 expands inresponse to rising temperature which develops on firing of the flashbulb. The expanding drop 53 pushes the diaphragm 52 against the tip 54awhereby the tip penetrates the diaphragm and comes in contact withmercury to thus close the switch including the contacts 54 and 55. Asstated before, the drop 53 is in permanent contact with the main'contact55. The well known phenomenon of surface tension insures that the switch54, 55 remains closed even after the temperature of mercury drops.

Without further analysis, the foregoing will so fully reveal the -gistof the present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of my contribution to the art.

What is claimed as new and desired to be protected by Letters Patent is:t

1. A multiple flash bulb holder, comprising a plurality of discreteflash bulbs including a first and a second ash bulb, each of said flashbulbs comprising separate first and second main contacts, a filamentconnecting said main contacts and arranged to undergo destruction inresponse to firing of the respective liash bulb, and a separate envelopesurrounding said main contacts and said filament; an electric circuithaving a pair of terminals connectable with a source of electricalenergy and normally open switch means comprising two contacts andarranged to close permanently in response to firing of said first flashbulb to thus prepare said second iiash bulb for firing, each of saidfirst main contacts being connected with one of said terminals and thesecond main contact of said first ash bulb being connected with theother terminal, said switch means being connected between the secondmain contacts of said first and second flash bulbs; and circuitcompleting means for connecting the contacts of said switch means toeach other in response to firing of said first flash bulb, said circuitcompleting means comprising a body of current-conducting materialprovided on one contact of said switch means, said material beingfusible at firing temperature of said first flash bulb to therebyestablish a current-conducting connection between the contacts of saidswitch means.

' 2. A holder as set forth in claim 1, wherein the contacts of saidswitch means comprise closely adjacent portions and said body ofcurrent-conducting material is provided on such portion of saidauxiliary contact.

3. A holder as set forth in claim 1, wherein said circuit completingmeans further comprises a receptacle consisting of heat-resistantmaterial and having a chamber arranged to collect saidcurrent-conducting material in response to fusing of said body, eachcontact of said switch g means comprising a portion extending into saidchamber so that the fused body connects such portions.

4. A holder as set forth in claim 3, wherein said receptacle consists ofa material selected from the group consisting of vitreous and ceramicsubstances.

5. A multiple flash bulb holder, comprising a plurality of discrete ashbulbs including a rst, a second and a third flash bulb, each of said ashbulbs comprising a separate first main contact, a separate second maincontact and a filament connecting said main contacts and arranged toundergo destruction in response to firing of the respective flash bulb;and an electric circuit having a pair of terminals connectable with asource of electrical energy andL normally open first and second switchmeans respectively arranged to close permanently in response to ring ofsaid first and'second flash bulbs, each of said first main contacts being connected wit-hone of said terminals and the second main contact ofsaid first flash bulb being connected with the other terminal, saidfirst switch means being connected between the second main contacts ofsaid first and second flash'bulbs so that said second fiash bulb can bered subsequent to firing` of said first ash bulb and onresultingclosingof said first switch means, said second switch means being connectedbetween the second main contacts of said second and third ash bulbs sothat said third iiash bulb can be fired upon firing of said second ashbulb and on resulting closing of said second switch means, the secondmain contact of said third ash bulb being then connected with said otherterminal by way of said first and second switch means.

6. A multiple ash bulb holder as defined in claim 5, wherein each ofsaid flash bulbs comprises a separate envelope.

7. A-multiple ash bulb holder as defined in claim e', wherein each ofsaid switch means comprises a pair or contacts and further comprisingcircuit-completing means for respectively connecting the-contacts ofsaid first and second switch means to each other in response to firingof said first andsecond fiash bulbs;

8. A multiple ash bulb holder as defined in claim 7, wherein saidcircuit completing means comprises a resilient elementof'current-conducting material provided on the second main contact ofeach of said first and second flash bulbs and permanently tending toengage one contact of said first and second switch means respectively,each of said resilient elements being held away from said one contact ofthe respective switch means bythe filament of'said rst and. second Hashbulb respectively and being free to engage the respectiveone contact inresponse to destruction of thegcorresponding filament.

9. A multiple flash bulb holder as defined in claim 7, wherein saidcircuit completing means comprises bodies of current-conducting materialeach being in permanent contact with one contact of said first andsecond switch means and being expansible in response to-a rise intemperature on firing of said ,first andV second ash bulb respectivelyto thus establish a current-conducting connection between said onecontact and the other contact of the respective switch means. l

10. A multiple liiash bulb holder as defined in claim 9, wherein'each ofsaid bodies consists of mercury.

11. A multiple flash bulb holder, as defined in claim 10, wherein eachof said first `and second ash bulbs comprises an envelope defining achamber for the respective body, said circuit completing means ,furthercomprising a pair of'separator means each consisting Iof readilypenetrablematerial and disposed between one of said bodies and a pointedportion of the other contact of the respective switch means so that,when one of said bodies expands, the pointed portion of 4the otherlcontact of the respective switch meanspenetrates through thecorresponding separator and moves intoA current-conducting engagementwith mercury, said bodies being respectively in permanentcurrent-conducting contact with the second main contacts of said firstand second liash bulbs.

12. A multiple flash bulb holder, comprising a plurality of ash bulbsincluding a rst and a second ash bulb, each of said flash bulbscomprising a rst main contact, a second main contact and a iilarnentconnecting said main contacts and arranged to undergo destruction inresponse to tiring of the respective ash bulb; and an electric circuithaving a pair of terminals connectable with a source of electricalenergy, said rst main contact of each ash bulb being connected with oneof said terminals and the second main Contact of said rst flash bulbbeing connected with the other terminal, normally open switch meansarranged to close permanently in response to tiring of said rst flashbulb to thus prepare said second ilash bulb for tiring, said switchmeans comprising the second main Contact of said rst ilash bulb and anauxiliary contact which is normally insulated from said last namedSecond main contact and is connected with the second main contact ofsaid second ash bulb, circuit completing means for connecting thecontacts of said switch means to each other in response to ring of 20said rst flash bulb, a charging capacitor connected in 10 parallel withthe main contacts of said first ash bulb, a source of electrical energyconnected in circuit with said charging capacitor, and a secondcapacitor connected in parallel between the main contacts of said firstand second Hash bulbs, the capacitance of said second capacitor beingless than that of said rst capacitor.

References Cited UNITED STATES PATENTS 2,191,402 2/1940 Sair et al.431-93 X 2,290,309 7/ 1942 Aquilla 431-93 2,817,963 12/1957 Scholkemeier431-93 3,220,225 ll/1965 Baird 431-95 FOREIGN PATENTS 1,192,047 4/ 1965Germany.

EDWARD 3'. MICHAEL, Primary Examiner US. Cl. X.R.

